Drilling tool

Abstract

In a drilling tool including: a shank located at a tip side of a tool main body; and a bit located at a tip side of the shank, the shank and the bit (connection body) are connected to each other via screws, and a guide part for center alignment for aligning the centers of the shank and the bit is formed in the vicinity of screw portions of the shank and the bit.

The invention claimed is: 
     
       1. A drilling tool comprising:
 a tool main body; 
 a shank extending along a longitudinal axis located at a tip side of the tool main body; and 
 a connection body located at a tip side of the shank, 
 wherein the shank and the connection body are connected via screw portions of the shank and the connection body, 
 wherein a guide part for aligning centers of the shank and the connection body along the longitudinal axis is formed in the vicinity of the screw portions of the shank and the connection body, 
 wherein the guide part includes a tubular portion formed in front of a female screw portion of the shank and a base shaft portion formed at a base of a male screw portion of the connection body, and 
 wherein a distal-most end face of the shank facing the connection body is formed as an inclined plane that is inclined with respect to the longitudinal axis and forms an inclined gap between the distal-most end face of the shank and an end face of the connection body, the inclined gap being wider on one side of the longitudinal axis than on an opposite side of the longitudinal axis by the distal-most end face of the shank being formed as the inclined plane, the inclined gap extends radially outward from the guide part to the outermost surface of the shank and the connection body to discharge cuttings during rotation of the shank and the connection body. 
 
     
     
       2. The drilling tool according to  claim 1 , wherein the connection body is a bit. 
     
     
       3. The drilling tool according to  claim 1 , wherein the connection body is a main body shaft. 
     
     
       4. The drilling tool according to  claim 1 , wherein the connection body is an adaptor. 
     
     
       5. The drilling tool according to  claim 4 , wherein a distal-most end face of the adaptor which is connected to a bit is inclined with respect to the longitudinal axis. 
     
     
       6. The drilling tool according to  claim 4 , wherein a distal-most end face of the adaptor facing the main body shaft is inclined with respect to the longitudinal axis. 
     
     
       7. The drilling tool according to  claim 1 , wherein the guide part comprises a fitting portion and a fitted portion, which are axially fitted to each other. 
     
     
       8. The drilling tool according to  claim 1 , wherein a plurality of the guide parts are formed. 
     
     
       9. The drilling tool according to  claim 1 , wherein an abutting portion for restriction a depth of a screw connection is formed in the guide part. 
     
     
       10. The drilling tool according to  claim 1 , wherein a distal-most end face of the shank facing a main body shaft is inclined with respect to the longitudinal axis. 
     
     
       11. The drilling tool according to  claim 1 , wherein the inclined gap is open outwardly from the guide part in a radial direction so as not to form an enclosed space.